Fluid flow regulators (controllers) provide a constant flow rate by means of a pressure differential regulating device that senses changes in upstream or downstream fluid pressure and compensates for the change. Conventional regulating devices use an impeller or a piston that is sensitive to a variable incoming fluid pressure, P1, and a downstream fluid pressure, P2. The piston reduces a valve opening when the differential pressure between P1 and P2 increases and enlarges the valve opening when the pressure differential between P1 and P2 is reduced.
Examples of such regulators may be found in U.S. Pat. Nos. 5,931,191 issued Aug. 3, 1999, to Frank A. Taube, John D. Taube, and Peter H. Greverath for xe2x80x9cFlow Control Valve for Passing Two Fluids in Opposite Directonsxe2x80x9d; U.S. Pat. No. 5,913,328 issued Jun. 22, 1999 to John D. Taube, Peter H. Greverath and Eric Geile for xe2x80x9cFlow Control Valve with One Piece Plug/Valve Tube Sleeve Assemblyxe2x80x9d; and U.S. Pat. No. 5,979,495, issued Nov. 9, 1999, to Frank A. Taube and Anthony J. Vizzini for xe2x80x9cAdjustable Low Flow High Pressure Regulatorxe2x80x9d. In each case the flow rate of the regulator is adjusted by an adjusting means, such as a needle valve, disposed in a fluid passage that connects incoming fluid pressure P1 on one side of the impeller, to the opposite side of the impeller which is at pressure P2.
The broad purpose of the present invention is to provide an improved fluid flow controller in which the flow rate adjusting valve is mounted on the controller body adjacent one end of the impeller chamber. The piston is balanced by the incoming pressure at P1 acting against one side of the piston, the adjusted fluid pressure P2 biasing the opposite side of the piston, and an impeller spring. The piston moves to either open or close a variable orifice or port connecting the impeller chamber to the outlet opening in response to changes in either the inlet fluid pressure or the outlet fluid pressure.
The preferred controller comprises a minimal number of components that can be easily manufactured.
Still further objects and advantages of the invention will become readily apparent to those skilled in the art to which the invention pertains upon reference to the following detailed description.